Lubricant



Patented June 20, 1944 UuI Ul l UHUUU HL! L-HLIUL.

LUBRICANT Alfred L. Bayes, Kenmore, N. Y., assignor to Carbide and Carbon Chemicals Corporation, a corporation of New York No Drawing. Application December 26, 1942, Serial No. 470,213

21 Claims. (Cl. 252-47) The invention relates to lubricants, and particularly to mineral oil lubricants having incorporated therein minor quantities of additive material adapted to improve lubrication properties, and to inhibit or retard corrosion and deterioration of the oil in normal lubrication service.

Commercial petroleum lubricating oils, .as originally extracted and refined, may have certain corrosiveness toward metals. This is particularly true of those oils which are refined by a solvent extraction process. Oils which are not initially corrosive may become so under conditions of use in an internal combustion. engine, where oxidation, under high temperature and pressure, usually effects certain break-down in the oil, which i-ypromotes or creates corrosive con-' ditions, as well as other deteriorating influences. In" modern automotive engines the bearing metals often cadmium-silvgnidmiiumare especially susceptible 'to corrosion incontact with mineral lubricating oils. The problem of inhibiting the corrosive action of oils on metal surfaces, and of retarding deterioration of the 1 oil through oxidation, are, therefore, of essential oxidatiom Theadditives proposed for this purpose are dimorpholine polysulfides of the characteristic structure:

in which :1: represents two or more sulfur atoms. Individual compounds of this structure, like dimorpholine disulflde, or .products comprising mixtures of these polysulfides, including the trisulfide, tetrasulflde, or higher derivatives, are included within the broader scope of the invention.

Dimorpholine disulfide, of the formula:

can be prepared by the interaction of sulfur monochloride with morpholine in an inert solvent like toluene. The purified compound is a white crystalline solid containing 27.1% sulfur, and having aineltingpoint of about 123 C. A prod- "hickeY-or-copper-leadalloys, .and these alloys not comprising mixtures of these polysulfides can be made by reacting the morpholine with elemental sulfur in the presence of lead oxide or other metal oxide catalyst. By modification in the mol proportions of the reactants used, in the quantity and purity of the catalyst, or in the temperature of the reaction, products of different sulfur content can be obtained, with the sulfur varying, for example, within the range of about 32% to 42%. The melting point of these compound mixtures is not. sharply defined, although the products usually melt within the range of 75% C. to 85% C.,with the melting temperature decreasing as the sulfur content increases. Also with increase in ulfur content, the recovered *solid products vary from white to yellow incolor.

As already indicated, these new additives iin oil solution exert both an anti-oxidant andza corrosion inhibiting, actionr .It. 'appears; heir;v

ever, that to obtain the optimum. in eachubf these functions, the additive product should have a sulfur content intermediate in the range above specified, since low sulfur is better for corrosion =:protection, whilea high sulfur content improves engine cleanliness. Polysulfide mixtures with a sulfur content of from about 32% to' 39% are thus preferred for their over-all inhibitor action.

These products can be obtained directly by the litharge method as described, or they can be made by mixing a low sulfur compound, like the disulfide, with products of higher sulfur content. By another alternative an auxiliary inhibitor, for either oxidation or corrosion'as desired, might be used along with dimorpholine polysulfides.

The most effective concentrations of the additives will vary with different lubricating oils,

and with different lubrication conditions, but for most purposes amounts within the range of 0.10% to 5.0% by weight will be found satisfactory. For greater permanency in the inhibitor action a minimum of about 0.5% is' preferred, and and without the aid of solubilizers, about 2.0% of the additive is all that can be dissolved in most mineral lubricating oils. Higher concentrations may, however, be desirable in special applications, such as in extreme pressure lubrillvvll uninhibited oil after both a 54 hour Lauson engine test and a 36 hour run in a Chevrolet engine. The oil used in the tests of Tables 1 and 2 was a Pennsylvania solvent extracted oil, o'f vis cosity S. A. E. 10, and the Chevrolet engine test was made with a mid-continent solvent extracted oil of viscosity S. A. E. 20.

and 3, expressing the present change in viscosity, the increase in percentagev carbon, and the milligram increa'sesffor neutralization number, naphtha insolubles' and chloroform solubles, over the corresponding value for the oil before test, give a good indication of the changes effected in the oil by engine operation.

The invention contemplates usage of these new TABLE 1 additives in anyof the common petroleum lubri- 10 cating oils, including both asphaltic and parafgf ffg fin base oils, and those refined by difierent known Additive used g fi methods. Modifications, particularly to deter- CdNi Aged mine the most suitable concentration of the additive, may be necessary for different grades of None Q80 M 5 oil, and further additions of a detergent, an 0.5% dimorpholine polyoiliness agent, or other property-modifying maggf g fiia fifgfiifibif 3&9 M M02 terials, may alsoattimes be-desirable.

sulfide In fact, as another embodiment of this inveng i f f ff fg f f ffj 211 M8 M95 tion, I have found'a group of detergents which in mixture with the dimorpholin'e' polysulfides ,Noloss exert an unusually good cooperative inhibiting TABLE 2 action. These detergents: are metal-organic compounds, or more specifically, metal derivatives oi 54-hour Lauson engme test acetoacetic esters, particularly those esters containing an alkyl substituent having sixorinore Increase carbon atoms. Compounds of the metals'cobalt, Additive used 33%, chromium, nickel, calcium-andmagnesium, as

it 031532 m gifjg gh derived from niethyhamyl acetoace tate, are especially preferred for their detergent action, and PTcmt in combination withfldimorpholine polysulfldes, ',None 35.0 0. 87 1.42 will producea multi-functioned inhibitor eifect ;55 M3 M6 Q34 substantially enhancing lubricant performance. 1 0% dimo 11531 The relative amounts most suitable of these two ga a g gfiafifi' .3 731%,, '99 9: 7 componentsnwillnvary iwithihelgradeiandlnnd n .disulflde 27.1 19.8 (195 35 of oil to which-the mixture is added,'as is the case with the 'polysulfldes aloneg but' usually TABLE3 36-hour Chevrolet engine test I Inaease in' suum- Addmveused content Vis. at Per cent Neut. No. N C S 100 F. carbon Mg.KOH/gm.

Per cent z I 312 Sififiififiiififi ii2Zifi$f .it::;:::: 2721 1918 0:97 0:43 15 1 N. I.-Na htha insolubles. I-C. S.O oroform solubles. I

The Underwood test is well known to oil a quantity of each ingredient equal to about investigators, and represents severe corrosion and 0.2% to 1.0% by weight of the oil sufficient to oxidation inducing conditions. Oxidation catagive marked improvement. An additive mixture, lysts are sometimes used to further accelerate for example, composed of 0.5% of the dimorthis test, and here also the tests were conducted pholine polysulfide product and 0.5% calcium in the presence of an iron naphthenate catalyst methyl amyl acetoacetate has shown a performin amount equivalent to 0.01% ferric oxide. The ance, in comparison with an uninhibited oil, as bearing compositions are the same as those now indicated in the following table. The tests were commonly used in internal combustion engines. made with a mid-continent il ofviscosity. S. A. The values for viscosity, Conradson carbon resi- E. 20, and the analysis taken after a 36 hour run due, and other properties indicated, were all dein a Chevrolet engine. v

TABLE 4 Engine ou-rb i i fs big-1g Vis at Per cent Neut No grams F. carbon M ren gm.

Per cent Uninhibited oil 157 0. 711 262 a. o 6.2 229 119 on with inhibitor 173 0.154 19 0. 76 o. 34 15 2 I designates an entirely clean engine and 0 a dirty engine.

termined in accordance with established A. S.

It will be understood that the specific mixture T. M. methods, and the figures given in Tables 2 75 shown is merely illustrative-of many multi func- 252. COMPOSITIONS- CROSS REERENCE Search 30 tioned additives which may be formulated from the two components described, and the invention includes all modifications in which dimorpholine polysulfides of the structure specified constitute an essential corrosion and oxidation inhibitor, 5 CHPCH: CHPCH, whether used alone or with other additive ingredients. The claims should also be interpreted in accordance with the disclosure given, and are GHQ-CH1 UHF-CH1 intended to Cover, Within the b o e e ce 150 and being the product of the reaction in an inert d p o polysulfides, a reaction p odu solvent of sulfur monochloride with morpholine. which is a substantially pure compound, like di- 8. A lubricant comprising a mineral oil conm p in disulfide, r those products which taim'ng corrosion and oxidation inhibiting constitute mixtures of the disulfide with trisulamounts of a mixture of oil-soluble dimorpholine fide,-tetrasulfide or higher sulfur derivatives. polysulfides of the structure: a -I claim: rim-0H, CHz-CI-Ia l. A lubricant comprising a mineral oil containing corrosion and oxidation inhibiting N- (S) N amounts of an oil-soluble dimorpholine polysul- CHPCH2 uni-CH: fide the Structure! wherein x is at'least two; and an oil-soluble metal GET-0H2 GHQ-cm derivative of'an acetoacetic ester. 0 O 9. A lubricant comprising a petroleum lubrieating oil containing an additive mixture com- CHT'CHZ CHPCH? posed of corrosion and oxidation inhibiting wherein :1: is at least two. amounts of an oil-soluble dimorpholine polysul- 2. A lubricant comprising a mineral oil confide of the structure: taining corrosion and oxidation inhibiting CHPCH: CHPCH amounts of an oil-soluble dimorpholine polysulfide of the structure: GHPCH: CH2 CH2 GHQ-0H2 CH2CH2 O wherein a: is at least two; and detergency amounts of calcium methyl amyl acetoacetate. Gib-CH2 GET-CH 10. A lubricant'comprisin'g a' petroleum lubriwherein :1: is at least two and represents a sulfur eating oil containing an additive mixture comc e t of o a o to 42%. posed of corrosion and oxidation inhibiting 3. A lubricant comprising a petroleum lubriamounts of an oil-soluble dimorpholine polysuleating oil containing corrosion and oxidation infide of the structure: hibiting amounts of a mixture of dimorpholine F CHPCH, polysulfides of the structure: 4

o 1 O.N- ZN CH2CH: CHr-CHn 40 I V GHQ-CH: OHr-CH; -o N- s),N o s a, v

\ wherein 1: is at least two; and detergency CHPCE amounts of cobalt methyl amyl acetoacetate; wherein is at least 11.A lubricant comprising a petroleum lubri- 4. Alubricant comprising a petroleum lubri- Gating O t ir l ng an additive mixture corncating oil containing corrosion and oxidation in- Posed of corroslm and W mhlbltmg hibiting amounts of a mixture f dimorpholine amounts of an oil-soluble dimorpholine polysulpolysulfides of the structure: fide of the structure:

CH2 CH2 CH, OH2 CHrCEz CHr-CHI O N- ),N o N( ),N

\ cn on \CH on CHz-CH: CH2-C H2 2- 2 wherein m is at least two, said mixture being the wherein. 93 15 least w and detergency product of the reaction of elemental sulfur with amounts of (fhromlum f i amyl acetoacetat? morpholine in the presence of a lead oxide cata- A lubncant petroleum lubn lyst' eating oil containing an additive mixture corn- 5. A lubricant comprising a petroleum lubri: posed about 02%) 10% of mlxture of eating oil containing corrosion and oxidation inmorpholme polysulfides of the structure: hibiting amounts of a mixture of dimorpholine T- Q- polysulfides of the structure: O

cnkcm CHz-CE: fl, N(S) N wherein :n is at least two; and about 0.2% to 1.0%

CEPO I CHPCHZ of a metal derivative of methyl amyl acetoacewherein at is at least two, representing asulfur tatecontent of from about 32% to 42%. l3. A lubricant comprising a petroleum lubri- 6. A lubricant comprising a petroleum lubricatmg O11 contammg an addltlve ntlxture con}- cating oil containing corrosion and oxidation inpose'd of.about 02% to 10% of i mIXtuIIe of alhibiting amounts of dimorpholine disulfide, said molpholme polysulfides of the S ructure' compound having the structural formula: 01124373, CHz-CH: O N S S N/ \O CHz-CH2 CH:--CH2 om-on, H, wherein a: is at least two and represents a sulfur 7. A lubricant comprising a petroleum lubricating oil containing corrosion and oxidation inhibiting amounts of dimorpholine disulfide, said compound having the structural formula:

content of from about 32% to 42%; and about 0.2% to 1.0% of calcium methyl amyl acetoacetate.

14. A lubricant comprising a petroleum lubricating oil containing an additive mixture composed of about 0.2% to 1.0% of dimorpholine disulfide, said compound having the structural formula:

and about 0.2% to 1.0% of a metal derivative of methyl amyl acetoacetate.

15. Method of lubricating bearing surfaces composed of metal having the corrosion susceptibility of copper-lead and cadmium-silver alloys, which comprises applying to the bearing surfaces a lubricant having incorporated therein, in corrosion-inhibiting amounts, a dimorpholine polysulfide of the structure:

wherein a: is at least two.

16. Method of lubricating bearing surfaces composed of metal having the corrosion susceptibility of copper-lead and cadmium-silver alloys, which comprises applying to the bearing surfaces a lubricant having incorporated therein, in corrosion-inhibiting amounts, a mixture of dimorpholine polysulfides of the structure:

wherein a: is at least 2, and represents a sulfur content of from about 32% to 42%.

17. Method of lubricating bearing surfaces composed of metal having the corrosion susceptibility of copper-lead and cadmium-silver alloys, which comprises applying to the bearing surfaces a lubricant having incorporated therein, in corrosion-inhibiting amounts, dimorpholine disulfide of the structural formula:

18. Method of lubricating bearing surfaces composed of metal having the corrosion susceptibility of copper-lead and cadmium-silver alloys, which comprises applying to the bearing surfaces a lubricant having incorporated therein minor amounts of an additive mixture composed of an oil-soluble dimorpholine polysulfide of the structure:

wherein a: is at least two; and an oil-soluble metal derivative of an acetoacetic ester.

19. Method of lubricating bearing surfaces composed of metal having the corrosion susceptibility of copper-lead and cadmium-silver alloys, which comprises applying to the bearing surfaces a lubricant having incorporated therein an additive mixture composed of about 0.2% to 1.0% of a mixture of dimorpholine polysulfides of the structural formula:

CH2-CH2 CHz-CH:

O\ S),N CHz-CH: CH2CH:

and about0.2% to 1.0% of a metal derivative of methyl amyl acetoacetate.

21. Method of lubricating bearing surfaces composed of metal having the corrosion susceptibility of copper-lead and cadmium-silver alloys, which comprises applying to the bearing surfaces a lubricant having incorporated therein minor amounts of an additive mixture composed of about 0.2% to 1.0% of a mixture of dimorpholine polysulfldes of the structure:

wherein a: is atleast two and represents a sulfur content of from about 32% to 42%; and about 0.2% to 1.0% of calcium methyl amyl acetoacetate.

ALFRED L. BAYES.

CERTIFICATE OF CORRECTION.

Patent No. 2,551,657. June 2o, 19%.

ALFRED L. BAYES.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows:

0nd coluinn, line 15, for "7 c. to 85% c."

1+8, after the word "these" insert -are; page 2, second column, line 1, for "present" read per cent-'- Page 1, sec- 0rd of the case in the Patent Office. Signed and sealed this 8th day of August, A. D. 19M.

Leslie Frazer (Seal) Acting Commissioner of Patents.

read --75 C. to 85 o." line and that the said Letters Patent should 

